Structuring of Contract Types
Contract structure is one of the earliest and most consequential factors that determines how tax will be applied across a project. Some tax treatment is dictated by the way a contract is written rather than what work is performed, making contract design a key point of control for managing both cost and risk.
In lump-sum contracts — the most common in the industry — contractors are often treated as the end users of materials and are responsible for paying tax upfront. Time-and-materials contracts, however, can allow firms to separate taxable materials and potentially nontaxable labor, while cost-plus arrangements introduce additional complexity by raising questions about what costs, reimbursements, fees, or markups are included in the taxable base.
Tax treatment can also vary between prime contractors and subcontractors, creating the potential for inconsistencies, duplication, or gaps in tax application because multiple parties can be procuring materials, claiming exemptions, or assuming differing tax responsibilities. Further, prime contractors that use nonresident subcontractors can be held liable for nonresident subcontractor tax liabilities if proof of registration is not provided, bonds are not received, and/or estimated tax due is not withheld from nonresident subcontractor payments.
Taxability of Materials and Supplies
Building materials typically represent a large share of total construction project cost, and even small differences in how they are taxed can materially affect margins. Because purchasing decisions are often made early, they can be difficult to reverse if unfavorable tax implications emerge, embedding tax inefficiencies in a project’s financial structure.
Whether materials are taxable or exempt depends on factors such as end use, customer type, and jurisdiction. Purchasing responsibility is a critical variable — materials purchased directly by an exempt entity might not be taxable, while the same materials purchased by a contractor could trigger tax liability. Consumables, tools, and equipment are also often treated differently depending on jurisdiction, and those differences create layers of hidden costs that can accumulate across projects.
Tax Treatment of Labor and Services
In many jurisdictions, labor itself might be tax-exempt, but the way labor expenses are packaged, described, or bundled with materials costs can unintentionally make them taxable. As a result, seemingly minor administrative decisions, such as contract formatting or invoicing structure, can have direct financial consequences on tax treatment for labor and services. Further, authorities often treat installation, repair, and maintenance services differently from a tax perspective, so bundling labor with materials in a single contract could render otherwise nontaxable services subject to tax.
Application of Exemptions and Certificates
Exemptions are one of the few opportunities to reduce or eliminate sales and use tax liability. Many contractors either fail to capture available exemptions or expose themselves to audit risk by applying exemptions incorrectly. Exemption-related risk is often two-pronged: Firms can either overpay tax when savings were possible or accidentally underpay and face penalties.
Exemption eligibility often varies depending on the customer’s tax status, such as in the case of government or nonprofit organizations. It also varies based on the nature of the work, differing across manufacturing, research and development, or renewable energy projects. Proper application of exemption certificates by firms and contractors is critical for tax savings in construction projects because incomplete or missing documentation can result in automatic tax liability during an audit, regardless of whether the exemption would have otherwise applied.
Multistate and Local Tax Considerations
For contractors operating across jurisdictions, sales and use tax is a patchwork of competing rules that must be navigated simultaneously. Different jurisdictions can have distinct definitions for what qualifies as sales or use tax, as well as for TPP, real property, repair/maintenance-type services, or capital improvements. Taxability also might depend on whether goods are delivered to a ship-to location or job site, and working across state lines can trigger nexus and registration requirements.
Differences in local tax codes makes site selection highly important for value generation because variability across states and localities also increases the likelihood of inconsistent treatment, missed obligations, and audit exposure. Because of that complexity, companies might benefit from outside assistance in tax planning. But when working with a third-party tax advisor, firms should make sure to select one that understands all local requirements in every jurisdiction where they have established nexus.
A Total Tax Approach to Contracting and Construction
Sales and use tax is a structural component of how construction projects are priced, executed, and delivered. Contractors that solicit tax input early in a project’s lifecycle will be well-positioned to protect their margins and help reduce exposure. Incorporating tax into all areas of planning and procurement can help deliver more accurate pricing, improve alignment between stakeholders, and help reduce the likelihood of costly surprises.
